[SYSTEM DRIVE]>USERS>[ACCOUNT NAME]>LIBRARY
If you back up that folder, it should contain everything you need. If you want, you can go in and probably find each folder you need, but you can just backup the whole Library to be safe.
The folder [SYSTEM DRIVE]>LIBRARY contains settings that are system-wide, so you may want to back that up too, although things like Safari bookmarks or Address Book names are in the [ACCOUNT NAME] Library. Remember that things like your iTunes and iPhoto playlists are not in that folder. They’re in the other folders in your [ACCOUNT NAME] folder.
If you want to spend $99 for a .Mac account, it comes with a backup utility that stores your files on a server somewhere else. The nice thing about that is that it allows you to select the things you’re talking about from a checklist. Very simple.
https://www.mac.com/1/iTour/tour_backup.html
There are probably other programs you can buy that do this too, although I don’t know any since I just burn backup discs manually.